Changes
→Why not use the MSI version?: new section
Try yourself.
To be honest, WPKG doesn't support such checks yet (it can't expand %PROGRAMFILES%).
== Why not use the MSI version? ==
http://www.adobe.com/products/flashplayer/fp_distribution3.html
Problem is, that if you have old exe-based installations, you will see them twice under Software (the same problem like 7zip).